Collapse of a hot vapor bubble in subcooled liquid

• Published in: Journal of physics. Conference series Vol. 1652; no. 1; pp. 12018 - 12024
• Main Authors: Chung, Le T, Melikhov, V I, Melikhov, O I, Yakush, S E
• Format: Journal Article
• Language: English
• Published: Bristol IOP Publishing 01.10.2020
• Subjects: Cavitation; Computational fluid dynamics; Initial pressure; Kinetic energy; Mathematical models; Perturbation; Physics; Premixing; Steam explosions; Water vapor
• ISSN: 1742-6588; 1742-6596
• DOI: 10.1088/1742-6596/1652/1/012018

Numerical simulations are performed for a spherical bubble containing hot vapor in subcooled water. Unlike conventional cavitation problems, the initial pressure in the bubble and surrounding liquid are equal to each other. The physical mechanism for the appearance of pressure difference driving the bubble collapse is rapid cooling and condensation of vapor in the bubble. A model for the fluid dynamics and thermal processes in the bubble and in the liquid is presented. The governing equations are solved numerically in the transformed coordinates where the bubble size remains constant, with the Rayleigh-Plesset equation describing the time evolution of bubble radius. The effect of the initial superheat of vapor in the bubble with respect to the saturation temperature is studied. The bubble collapse of hot vapor is compared with an idealized case, resembling collapse of a cavitation bubble. Estimates for the kinetic energy of liquid gained in the course of bubble collapse are obtained. The results are applicable to the evaluation of the perturbations to spreading melt surface due to interaction with the unstable water-vapor interface, and to the evaluation of the premixing zone in the stratified steam explosions.